precision lowp float;
varying vec4 vColor;				
varying vec2 vTextureCoord;					
uniform sampler2D uSampler;								
void main(void)									
{
    vec4 c = texture2D(uSampler, vTextureCoord);
    float a = c.r;
    if (a < 0.6) { a = 1.0; } else { a = 0.0; }
    gl_FragColor = vec4(0.0,0,0.0,a);
}